chromium/third_party/angle/src/compiler/translator/tree_ops/RemoveUnreferencedVariables.cpp

//
// Copyright 2017 The ANGLE Project Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
//
// RemoveUnreferencedVariables.cpp:
//  Drop variables that are declared but never referenced in the AST. This avoids adding unnecessary
//  initialization code for them. Also removes unreferenced struct types.
//

#include "compiler/translator/tree_ops/RemoveUnreferencedVariables.h"

#include "common/hash_containers.h"
#include "compiler/translator/SymbolTable.h"
#include "compiler/translator/tree_util/IntermTraverse.h"

namespace sh
{

namespace
{

class CollectVariableRefCountsTraverser : public TIntermTraverser
{ … };

CollectVariableRefCountsTraverser::CollectVariableRefCountsTraverser()
    : … { … }

void CollectVariableRefCountsTraverser::incrementStructTypeRefCount(const TType &type)
{ … }

void CollectVariableRefCountsTraverser::visitSymbol(TIntermSymbol *node)
{ … }

bool CollectVariableRefCountsTraverser::visitAggregate(Visit visit, TIntermAggregate *node)
{ … }

void CollectVariableRefCountsTraverser::visitFunctionPrototype(TIntermFunctionPrototype *node)
{ … }

// Traverser that removes all unreferenced variables on one traversal.
class RemoveUnreferencedVariablesTraverser : public TIntermTraverser
{ … };

RemoveUnreferencedVariablesTraverser::RemoveUnreferencedVariablesTraverser(
    CollectVariableRefCountsTraverser::RefCountMap *symbolIdRefCounts,
    CollectVariableRefCountsTraverser::RefCountMap *structIdRefCounts,
    TSymbolTable *symbolTable)
    : … { … }

void RemoveUnreferencedVariablesTraverser::decrementStructTypeRefCount(const TType &type)
{ … }

void RemoveUnreferencedVariablesTraverser::removeVariableDeclaration(TIntermDeclaration *node,
                                                                     TIntermTyped *declarator)
{ … }

bool RemoveUnreferencedVariablesTraverser::visitDeclaration(Visit visit, TIntermDeclaration *node)
{ … }

void RemoveUnreferencedVariablesTraverser::visitSymbol(TIntermSymbol *node)
{ … }

bool RemoveUnreferencedVariablesTraverser::visitAggregate(Visit visit, TIntermAggregate *node)
{ … }

void RemoveUnreferencedVariablesTraverser::traverseBlock(TIntermBlock *node)
{ … }

void RemoveUnreferencedVariablesTraverser::traverseLoop(TIntermLoop *node)
{ … }

}  // namespace

bool RemoveUnreferencedVariables(TCompiler *compiler, TIntermBlock *root, TSymbolTable *symbolTable)
{ … }

}  // namespace sh